1. Field of the Invention
The present invention relates to communications interlink devices for connection of equipment used in subsea operations, such as equipment used in the subsea oil and gas industry, and to insulated conductive wire assemblies incorporated in such interlinks. Such interlinks may be in the form of pressure balanced oil-filled (PBOF) hose, or undersea cables containing electrical or fiber-optic conductors.
2. Related Art
Subsea communication systems or interlink devices generally employ electrical Ethernet through electrical telecommunications twisted pair cable, or are purely optical fiber communication systems that may be included in PBOF hose or as a special submarine cable. Purely electrical systems have some limitations in the subsea environment. Standard electrical input/output interconnects and electrical cables can only step out to a distance of around 50 meters. Per industry specifications, a land based 10/100BaseT Ethernet cable has a maximum transmission distance of 100 meters at standard atmospheric pressure, after which the signal performance may be unacceptable
Subsea PBOF hose interlinks or cables commonly contain silicone oil or other fluid to provide pressure compensation. Standard terrestrial Ethernet cable is adversely affected by submergence in oil, which causes a reduction in impedance, increased back reflection, reduced transmission power and the distance that a signal can be sent along the cable without increasing power. The longer the cable becomes, the more of a problem this becomes. The maximum transmission distance for subsea PBOF hose Ethernet interlink using terrestrial CAT cable is about 70 meters, so such interlinks are normally limited to 70 meters in length.